The present invention generally relates to a force application device for disk brakes.
Such force application devices are known in the art, see for example, European Patent EP 0 644 358 B1. In the cited patent, for the case of a disk brake having a braking force applied thereto, the brake linings and the housing, which for example may be constructed as a floating caliper, are elastically deformed in order to achieve force application. The linings and housing therefore form a force-absorbing system, which stores the elastic deformation energy of these two parts.
In the known force application device, as disclosed in the cited patent, energy for application of the disk brake is transmitted to the force-absorbing system using a force generator constructed as a spring brake actuator and referred to as a force cartridge. A lever equipped with a lever bearing, which is disposed in a fixed position relative to the force-absorbing system, is provided for energy transmission. This lever has two points of force application, a first point of force application with predetermined lever length, which acts on the force-absorbing system, and a second point of force application at a variable position of the lever arm for action on the force cartridge. To permit variation of the second point of force application, the force cartridge is mounted pivotally around a fulcrum, and an adjusting device for selecting the desired position of the second point of force application is provided.
In the known force application device, during reversal of the working travel, corresponding to release of the brake, a portion of the elastic deformation energy contained in the force-absorbing system is recovered and fed into the energy-storing force generator, thus increasing the energy in the force generator by the amount of the recovered deformation energy. With this principle of energy recovery, an alternating transfer of stored energy takes place from the force generator to the force-absorbing system on the one hand and from the force-absorbing system to the force generator on the other hand. Accordingly, energy efficiency is achieved in the known device.
However, the known force application device suffers from the disadvantage that the structural configuration of a lever with a fixed lever bearing, the lever-arm length necessary for adjustment, and the pivotally mounted force generator with the adjusting device necessary for swiveling require a relatively large installation space. Where the space available for the braking assembly is limited, as is the case in disk brakes for motor vehicles, it is difficult to use the known force application device given its greater space requirements.
Accordingly, it is desired to provide an improved force application device of the type mentioned in the introduction, that overcomes the shortcomings associated with the prior art, such as, for example, providing a device that occupies a smaller space than the known devices, while retaining the benefits of energy recovery.
Generally speaking, a force application device is provided that retains the energy recovery benefits of known force application devices, while obviating the space requirement shortcomings in the prior art.
In a first aspect of the present invention, a force application apparatus is provided for applying a braking force to a force-absorbing system of a disk brake including a force generating device for applying a variable force to the force-absorbing system, a proportioning device having at least two contoured surfaces, a lever pivotally coupled to the force application apparatus cooperating with at least one of the at least two contoured surfaces to deliver the varying force applied to the force-absorbing system, and an adjusting device for changing the position of the at least one contoured surface with respect to the lever to vary the force delivered to the force-absorbing system.
In another aspect of the present invention, the at least two contoured surfaces are constructed such that when the position of the adjusting device is adjusted to increase the force acting on the force-absorbing system, energy is liberated from the force generating device and when the position of the adjusting device is adjusted to decrease the force acting on the force-absorbing system, the force generating device absorbs at least part of the energy released by the force-absorbing system.
In a further aspect of the present invention, the at least two contoured surfaces comprise a first and a second cam plate as a unitary block disposed between the lever and the force generating device.
In another aspect of the present invention, the force generating device includes a precompressed spring at least partially disposed within a spring housing and wherein the spring housing cooperates with the proportioning device and lever to deliver the varying force applied to the force-absorbing system.
Accordingly, an object of the present invention is to provide a force application device that retains the energy recovery benefits of known force application devices, while obviating the space requirement shortcomings in the prior art.
Another object of the present invention is to provide a force application device that delivers a varying force to the force-absorbing system of a vehicle""s braking system using a force generating device and proportioning device.
Yet another object of the present invention is to provide the proportioning device with at least two contoured surfaces that are constructed such that when the position of the adjusting device is adjusted to increase the force acting on the force-absorbing system, energy is liberated from the force generating device and when the position of the adjusting device is adjusted to decrease the force acting on the force-absorbing system, the force generating device absorbs at least part of the energy released by the force-absorbing system, thereby establishing energy see-saw behavior.
Still other objects and advantages of the present invention will in part be obvious and will in part be apparent from the specification.
The present invention accordingly comprises the features of construction, combination of elements, and arrangement of parts which will be exemplified in the constructions hereinafter set forth, and the scope of the invention will be indicated in the claims.